排序方式: 共有247条查询结果,搜索用时 10 毫秒
71.
Considering the importance of scientific interactions, understanding the principles that govern fruitful scientific research is crucial to policy makers and scientists alike. The outcome of an interaction is to a large extent dependent on the balancing of contradicting motivations accompanying the establishment of collaborations. Here, we assembled a dataset of nearly 20,000 publications authored by researchers affiliated with ten top universities. Based on this data collection, we estimated the extent of different interaction types between pairwise combinations of researchers. We explored the interplay between the overlap in scientific interests and the tendency to collaborate, and associated these estimates with measures of scientific quality and social accessibility aiming at studying the typical resulting gain of different interaction patterns. Our results show that scientists tend to collaborate more often with colleagues with whom they share moderate to high levels of mutual interests and knowledge while cooperative tendency declines at higher levels of research-interest overlap, suggesting fierce competition, and at the lower levels, suggesting communication gaps. Whereas the relative number of alliances dramatically differs across a gradient of research overlap, the scientific impact of the resulting articles remains similar. When considering social accessibility, we find that though collaborations between remote researchers are relatively rare, their quality is significantly higher than studies produced by close-circle scientists. Since current collaboration patterns do not necessarily overlap with gaining optimal scientific quality, these findings should encourage scientists to reconsider current collaboration strategies. 相似文献
72.
Meeting the projected 50% increase in global grain demand by 2030 without further environmental degradation poses a major challenge for agricultural production. Because surface ozone (O3) has a significant negative impact on crop yields, one way to increase future production is to reduce O3‐induced agricultural losses. We present two strategies whereby O3 damage to crops may be reduced. We first examine the potential benefits of an O3 mitigation strategy motivated by climate change goals: gradual emission reductions of methane (CH4), an important greenhouse gas and tropospheric O3 precursor that has not yet been targeted for O3 pollution abatement. Our second strategy focuses on adapting crops to O3 exposure by selecting cultivars with demonstrated O3 resistance. We find that the CH4 reductions considered would increase global production of soybean, maize, and wheat by 23–102 Mt in 2030 – the equivalent of a ~2–8% increase in year 2000 production worth $3.5–15 billion worldwide (USD2000), increasing the cost effectiveness of this CH4 mitigation policy. Choosing crop varieties with O3 resistance (relative to median‐sensitivity cultivars) could improve global agricultural production in 2030 by over 140 Mt, the equivalent of a 12% increase in 2000 production worth ~$22 billion. Benefits are dominated by improvements for wheat in South Asia, where O3‐induced crop losses would otherwise be severe. Combining the two strategies generates benefits that are less than fully additive, given the nature of O3 effects on crops. Our results demonstrate the significant potential to sustainably improve global agricultural production by decreasing O3‐induced reductions in crop yields. 相似文献
73.
Association between translation efficiency and horizontal gene transfer within microbial communities
Tuller T Girshovich Y Sella Y Kreimer A Freilich S Kupiec M Gophna U Ruppin E 《Nucleic acids research》2011,39(11):4743-4755
Horizontal gene transfer (HGT) is a major force in microbial evolution. Previous studies have suggested that a variety of factors, including restricted recombination and toxicity of foreign gene products, may act as barriers to the successful integration of horizontally transferred genes. This study identifies an additional central barrier to HGT-the lack of co-adaptation between the codon usage of the transferred gene and the tRNA pool of the recipient organism. Analyzing the genomic sequences of more than 190 microorganisms and the HGT events that have occurred between them, we show that the number of genes that were horizontally transferred between organisms is positively correlated with the similarity between their tRNA pools. Those genes that are better adapted to the tRNA pools of the target genomes tend to undergo more frequent HGT. At the community (or environment) level, organisms that share a common ecological niche tend to have similar tRNA pools. These results remain significant after controlling for diverse ecological and evolutionary parameters. Our analysis demonstrates that there are bi-directional associations between the similarity in the tRNA pools of organisms and the number of HGT events occurring between them. Similar tRNA pools between a donor and a host tend to increase the probability that a horizontally acquired gene will become fixed in its new genome. Our results also suggest that frequent HGT may be a homogenizing force that increases the similarity in the tRNA pools of organisms within the same community. 相似文献
74.
Quartz crystal microbalance with dissipation monitoring (QCM-D) is used for real-time in situ detection of cytoskeletal changes in live primary endothelial cells in response to different cytomorphic agents; namely, the surfactant Triton-X 100 (TX-100) and bacterial lipopolysaccharide (LPS). Reproducible dissipation versus frequency (Df) plots provide unique signatures of the interactions between endothelial cells and cytomorphic agents. While the QCM-D response for TX-100 can be described in two steps (changes in the osmotic pressure of the medium prior to observing the expected cell lysis), LPS results in a different single-phase signal. A complementary analysis is carried out to evaluate the possible competitive effects of TX-100 and LPS through the QCM-D response to BAEC stress by analyzing the Df plots obtained. Experiments with non-toxic components (fibronectin or serum) produce a different QCM-D response than that observed for the toxic chemicals, suggesting the use of Df plot signatures for the possible differentiation between cytotoxic or non-cytotoxic effects. Observations obtained by QCM-D signals are confirmed by conducting fluorescence microscopy at the same time. Our results show that a fast (few minutes) sensing response can be obtained in situ and in real-time. The conclusions from this study suggest that QCM-D can potentially be used in biodetection for applications in drug screening tests and diagnosis. 相似文献
75.
76.
PfSR1 controls alternative splicing and steady‐state RNA levels in Plasmodium falciparum through preferential recognition of specific RNA motifs 下载免费PDF全文
Shiri Eshar Lindsey Altenhofen Alona Rabner Phil Ross Yair Fastman Yael Mandel‐Gutfreund Rotem Karni Manuel Llinás Ron Dzikowski 《Molecular microbiology》2015,96(6):1283-1297
Plasmodium species have evolved complex biology to adapt to different hosts and changing environments throughout their life cycle. Remarkably, these adaptations are achieved by a relatively small genome. One way by which the parasite expands its proteome is through alternative splicing (AS). We recently identified PfSR1 as a bona fide Ser/Arg‐rich (SR) protein that shuttles between the nucleus and cytoplasm and regulates AS in Plasmodium falciparum. Here we show that PfSR1 is localized adjacent to the Nuclear Pore Complex (NPC) clusters in the nucleus of early stage parasites. To identify the endogenous RNA targets of PfSR1, we adapted an inducible overexpression system for tagged PfSR1 and performed RNA immunoprecipitation followed by microarray analysis (RIP‐chip) to recover and identify the endogenous RNA targets that bind PfSR1. Bioinformatic analysis of these RNAs revealed common sequence motifs potentially recognized by PfSR1. RNA‐EMSAs show that PfSR1 preferentially binds RNA molecules containing these motifs. Interestingly, we find that PfSR1 not only regulates AS but also the steady‐state levels of mRNAs containing these motifs in vivo. 相似文献
77.
Zeinivand Motahareh Nahavandi Arezo Baluchnejadmojarad Tourandokht Roghani Mehrdad Golab Fereshteh 《International journal of peptide research and therapeutics》2020,26(2):1099-1106
International Journal of Peptide Research and Therapeutics - Hepcidin peptide is the dominant regulator of systemic iron metabolism. Studies suggest a dual role of hepcidin in neuronal iron load... 相似文献
78.
Maryam Zahedifar Ali Akbar Moosavi Zahra Zarei Mahshid Shafigh Fereshteh Karimian 《International journal of phytoremediation》2019,21(5):435-447
AbstractDespite the fact that cadmium (Cd) is a non-essential element for plants, it can influence nutrients and affect human health. Potassium (K) can influence the transportation of heavy metals (HMs) in soil-plant systems. Here, a greenhouse experiment was conducted to evaluate the effect of Cd and K fertilizers on the different partitioning forms of HMs, their concentrations, uptake in the shoots and roots of Ocimum basilicum. Treatments comprised 2 levels of Cd (0 and 40?mg kg?1) and three levels of K (0, 100, and 200?mg kg?1) from three sources, i.e. KCl, K2SO4, and K-nano-chelate. 40?mg Cd kg?1 increased the shoot (above ground parts) Cd concentration. Addition of K as KCl, K2SO4, and K-nano-chelate increased the presence of Cd in shoots by 86, 82 and 76%, respectively, compared to the control. Using the nano-chelate of K can increase the accumulation of Cd in plants grown on contaminated soils to lesser content than that of the other forms of K. Application of 40?mg Cd kg?1 reduced the concentration of Zn, Cu, and Mn in the shoot, but increased shoot Fe concentration. Transfer factor (TF), which is the ratio of metal concentration in shoot to its concentration in root, of the studied HMs, was significantly affected by Cd and K treatments. Therefore, the proper form and dose of chemical fertilizers should be applied in Cd-contaminated soils. 相似文献
79.
Yazdani Faramarz Shahidi Fereshteh Karimi Pouran 《Journal of physiology and biochemistry》2020,76(2):291-299
Journal of Physiology and Biochemistry - The balance of pro-angiogenic and anti-angiogenic factors has a significant role in the development of diabetic cardiomyopathy. The purpose of this study... 相似文献
80.
Kashanian S Askari S Ahmadi F Omidfar K Ghobadi S Tarighat FA 《DNA and cell biology》2008,27(10):581-586
The interaction of native calf thymus DNA with clodinafop-propargyl (CP), in 10 mM HEPES aqueous solutions at neutral pH 7.2, has been investigated by spectrophotometric, circular dichroism (CD), spectrofluorometric, melting temperature (Tm), and viscosimetric techniques. It was found that CP molecules could intercalate between base pairs of DNA as evidenced by hyperchromism in UV absorption band of DNA, an increase in melting temperature, a sharp increase in specific viscosity of DNA, induced CD spectral changes, and increase in the fluorescence of methylene blue (MB)-DNA solutions in the presence of increasing amounts of CP, which indicates that it is able to release the intercalated MB completely. All results suggest that the CP interacts with calf thymus DNA by an intercalative mode of binding. 相似文献